Overhead valve internal combustion engines



March 22, 1960 E. R. PAYNE 2,929,368

OVERHEAD VALVE INTERNAL COMBUSTION ENGINES Filed May 5, 1959 OVERIEAD VALVE INTERNAL COM- BUSTIGN ENGINES Eric R. Payne, Northiield, Birmingham, England, assignor to The Austin Motor Company Limited, Birmingham, England Application May 5, 1959, Serial No. 811,093 Claims priority, application Great Britain May 39, 1958 4 (Jlaims. (Cl. 123-55) This invention relates to overhead valve internal combustion engines of the kind in which the cylinder block is formed with cylinder bores inclined at a small angle, alternately one to the left and one to the right, with respect to a vertical plane (hereinafter referred to as the centre plane) in which the crankshaft axis is disposed, the arrangement being such as to enable a com pact arrangement of cylinder head and valve operating mechanism to be obtained.

A multi-cylinder overhead valve engine of the kind referred to, and according to the present invention, is characterised in that a camshaft for operating the valves through tappets, push rods and rockers is mounted in the upper part of the cylinder block between the upper ends of the relatively inclined cylinders with its axis in the centre plane.

In order that the invention may be clearly understood and readily carried into effect, it will now be more fully described with reference to the preferred embodiment illustrated in the accompanying drawing which is a fragmentary sectional and elevation of a multi-cylinder engine.

Referring to the drawing, It? is the engine cylinder block formed with cylinder bores 11 inclined at a small angle, alternately one to the left and one to the right, with respect to a vertical centre plane, and 12 are the pistons which operate in the bores 11 and are actuated by connecting rods 13 from a crankshaft (not shown) which has its axis disposed in said centre plane. A cylinder head casting 14, common to all the cylinders, is cored out to afford suction ducts 15, one for each cylinder, which are interconnected and runout in the upper surface of the cylinder head casting 14 in a central position into a common suction manifold 16 for connection to a carburretter. Exhaust ducts 17, one for each cylinder, are also cored in the cylinder head casting 14 and mm out into the longitudinal side faces thereof for communication with exhaust manifolds 18, one on either side.

The undersurface or joint face of the cylinder head casting 14 is machined flat, and the combustion chambers are afforded wholly by the upper ends of the cylinder bores 11, whilst the suction ducts 15 and exhaust ducts 17 are controlled by spring-loaded poppet type valves 19 which operate in valve stem guides 20 mounted in vertically disposed guide bores 21 formed in the cylinder head casting 14.

Sets of rockers 22 for operating valves 19 on the same side of the centre plane are pivoted on a separate rockershaft 23 disposed between said valves 19 and the suction manifold 16 in bearings 24, whilst a camshaft 25, for operating all the valve rockers 22, each through a push rod 26 and a tappet 27, is mounted in the upper part of the cylinder block between the upper ends of the relatively inclined cylinders with its axis in the centre plane. The cam operated tappets 27 slide in bores 28 formed in the cylinder head casting 14, which bores 28 are radial to the camshaft axis and are inclined upv 2,929,368 Patented star. 22, 1950 wardly and outwardly from said centre plane; the bores 28 for the sets of tap-pets 27 which operate the rockers 22 on either rockershaft 23' being inclined toward the rate rockershafts 23, each with its complement of rockers 22, one on each side of the centre plane, and two inclined sets of tappets 27 and associated push rods 26 for operating the valves 19 to either side of said centre plane respectively.

The invention lends itself not only to a compact cylinder head construction and valve gear lay-out, but it also enables the cylinder head with the tappets, push rods, rockers and valves to be removed as a unit without disturbing the valve timing by virtue of the fact that the camshaft for operating the valves, and which is positively driven in the conventional manner from the crankshaft, is in the cyinder block.

Having fully describe-d my invention, what I claim and desire to secure by Letters Patent is:

1. A V-type multi-cylinder overhead valve engine having a cylinder block provided with cylinder bores inclined at a relatively slight angle alternately to the left and right with respect to a vertical center plane intermediate said bores, said block being provided with a flat upper face, a cylinder head having a flat lower face secured to the upper face of said block so that said faces lie in a wholly fiat joint plane, said cylinder head being cored to provide valve controlled suction and exhaust ducts, the exhaust ducts extending to the longitudinal side faces of the cylinder head, exhaust manifolds, one on either side of said cyilnder head respectively connected to said exhaust ducts, said suction ducts being interconnected and having a common suction manifold positioned in said center plane, a camshaft positioned in said block and disposed in said center plane just below said fiat joint plane, a plurality of valves carried by said cylinder head, and means operatively connecting said camshaft and valves.

2. A multi-cylinder overhead valve internal combustion engine as claimed in claim 1, wherein there are two separate rockershafts, each provided with rockers mounted on the cylinder head, one to each side of the centre plane, and two sets of tappets and associated push rods for operating the valves to either side of said centre plane respectively.

3. A multi-cylinder overhead valve internal combustion engine as claimed in claim 2, wherein the two sets of tappets slide in bores in the cylinder head, said bores being radially disposed to the camshaft axis and inclined upwardly and outwardly from said centre plane, one set toward one side thereof and the other set to the opposite side thereof, so that the upper ends of the push rods will engage the inner or tail ends of said rockers at positions between the respective rockershafts and said centre plane.

4. The engine of claim 3 wherein the valves are vertically arranged and positioned on either side of said common suction manifold.

References Cited in the file of this patent UNITED STATES PATENTS 1,276,389 Mason et al Aug. 20, 1918 1,293,279 Wilbee Feb. 4, 1919 1,443,856 Townsend Jan. 30, 1923 1,500,166 Van Ranst July 8, 1924 1,531,430 Wrentmore Mar. 31, 1925 FOREIGN PATENTS 336,841 Great Britain Oct. 30, 1930 

